First World War service To boost the rate of production, quantity orders for the DH.9 were also placed with Alliance, G & J.Weir, Short Brothers,
Vulcan,
Waring & Gillow and National Aircraft Factories No. 1 and No. 2. The first deliveries of the type occurred during November 1917 to
108 Squadron RFC; by the end of 1917, a total of five DH.9s had been delivered and passed their final inspections. The first combat engagement of the type, performed over France, was performed in March 1918 by
No. 6 Squadron RNAS. By July 1918, a total of nine operational squadrons deployed to the
Western Front were using the type. The DH.9's performance in action over the Western Front was typically deemed to have been a disaster; heavy losses of the type were quickly incurred, attributed to both its poor performance and to engine failures, despite the prior derating of its engine to reduce the failure rate. On multiple occasions, less than half of a flight of bombers would reach their intended targets; according to Bruce, the successful missions performed by the DH.9 were frequently a product of "the courage and determination of the pilots and observers that flew them". Squadrons would often implement their own home-built enhancements to their aircraft, such as enlarged
carburetor air intakes and modified fuel mixture controls. On 9 August 1918, Lieutenant E.A. Simpson of 49 Squadron, while flying a bombing mission upon bridges at
Falvy and
Bethencourt, shot down four hostile fighters while defending against repeated attacks upon the formation. In another instance, Captain
John Stevenson Stubbs achieved 11 aerial victories in a DH.9, including the highly unusual feat of
balloon busting while flying the type. Despite its general lack of performance, due to its large numbers, the DH.9 was introduced to nearly every theatre of the conflict prior to the signing of the
Armistice of 11 November 1918, which ended the conflict. The last combat use of the DH.9 by the RAF was in support of the
final campaign against
Diiriye Guure in
Somalia during January–February 1920. Amongst the aircraft used in Somalia, one DH.9 was modified to function as an
air ambulance, being able to load and transport a single stretcher, which was carried on the upper
longerons directly to the rear of the pilot's cockpit. Further ambulance conversions were performed, including a number that were operated by the
Royal Netherlands Air Force. The
South African Air Force (SAAF) received a total of 48 DH.9s, and used them extensively, including against the
Rand Revolt in 1922. Several South African aircraft were later re-engined with
Bristol Jupiter radial engines as the
M′pala; such modified aircraft continued to serve until 1937. Greeks had deployed a number of them against the
Kemalists who were fighting the British supported Greek Army invading the remaining chunk of the
Ottoman Empire after the 1918
Armistice of Mudros followed by the
Sevres Treaty which was rejected by the nationalists. One of Greek DH.9s had made a forced landing behind Turkish lines near
Muğla during the
Battle of Sakarya the previous year, sometime in July 1921. This machine was quickly repaired and was flown to Ankara in August 1921 by
Vecihi Hürkuş. It was named "Ismet" and deployed, as the only Turkish airplane at the time, in the last phases of the Battle of Sakarya, making a total of 23 sorties, mostly by Vecihi. Same airplane continued to serve for the remaining of the War of Independence through 1922. There were three more Greek DH.9s found in excellent condition, with plenty of spare parts, near
İzmir after the Greek army pulled out hurriedly, having been routed by Kemalists in August 1922. These four planes served the young
Turkish Air Force until 1925.
Civilian service After the end of the war, large numbers of surplus DH.9s became available, having been deemed to be surplus to requirements by their original military operators; accordingly, many were resold onto civil operators, such as by early aerial transport companies. Large numbers were modified to better perform as transport aircraft, such as the cabin being suitably adapted for the carriage of passengers. Several aircraft were reconfigured to serve as
trainer aircraft, being refitted with
Armstrong Siddeley Jaguar engines and rubber undercarriages; designated as DH.9Js, the last of these were withdrawn and scrapped in 1936. A number of different DH.9 conversion programmes for civil use were carried out, both by Airco and its successor, the
de Havilland Aircraft Company, and by other third party companies, such as the
Aircraft Disposal Company. Some radial powered DH.9Js continued in civil use until 1936. One DH.9 was transported to Japan during the
Sempill Mission. A large number of DH.9s were also apparently exported to China according to the
Aircraft Disposal Company. ==Variants==